Changshan County, under the jurisdiction of Zhejiang Province, is located in the southwest of Zhejiang Province, the west of Jinqu Basin, the upstream of Qiantang River, adjacent to Qujiang District in the east, Jiangshan City in the south, bordering Yushan County of Jiangxi Province in the southwest, adjacent to Kaihua County in the northwest, and adjacent to Chun 'an County of Hangzhou in the northeast. The people's government of Changshan County is located at No. 29, Shengli Street, Tianma Street Road. The county covers an area of 1099 square kilometers, with jurisdiction over 3 subdistricts, 6 towns, 5 townships, 180 administrative villages and 10 communities. According to the seventh census, as of midnight on November 1, 2020, Changshan County had a permanent population of 259,966.

In the twenty-third year of Jian 'an in the Eastern Han Dynasty (218), the county was founded, and it was called Dingyang. In the fifth year of Xianheng in the Tang Dynasty (674), Fen Xin 'an set up Changshan County in the former Dingyang County, named after Changshan (also known as Changshan Mountain, namely today's Hushan Mountain) in the south of the county, and Changshan County as the name since then; Changshan County is rich in mineral resources. There are 38 varieties of mineral resources discovered in Changshan County, among which the reserves and grades of limestone, stone coal and quartz ore all rank first in Zhejiang Province.

Changshan County is one of the second batch of pilot areas of Zhejiang high-quality development and construction of common prosperity demonstration zone, national health township (county).
In 2021, Changshan County achieved a gross regional product (GDP) of 18,757.87 million yuan, an increase of 9.8% over the previous year at comparable prices. The value added of the primary industry was 829.93 million yuan, up by 2.9%; The added value of the secondary industry was 8,540.57 million yuan, up by 11.9%; The value added of the tertiary industry was 938737 million yuan, up by 8.8%.